When one practices land sports such as skiing, skating, mountain climbing or hiking, or marine sports, or drives a bicycle or a motorcycle with wearing spectacles or goggles, the spectacles or goggles may sometimes be fogged or steamed over. In particular, when one moves between the conditions where the temperatures and humidities are remarkably different each other, the spectacles or goggles tend to become steamed over. By way of illustration, when the outside air temperature is low, the outside surfaces of the spectacles or goggles are exposed to the low temperature, and, the temperature of the inside raises due to a body heat and the humidity increases due to sweating to become dew point or higher, and hence the spectacles or goggles are fogged or steamed up. Further, the spectacles or goggles are steamed over due to a breath (sigh). Among other situations, when one wears goggles, the fogging or steaming up can hardly be removed since the goggles form almost sealed spaces.
Japanese Patent Application Laid-open No. 165724/1986 (JP-A-61-165724) relates to cleaning and antifogging treatment of surfaces of spectacles, and discloses a process which comprises flowing a treating agent impregnated and held on a holding part to a coating part with the use of capillarity phenomenon, cleaning the surfaces of spectacles on the coating part and treating the surfaces with a treating agent. According to this technology, however, a surfactant such as polyoxyethylene nonyl phenol and the like is used as the antifogging agent so that impartment of an eternal antifogging property for the spectacles would not be expected.
Japanese Patent Application Laid-open No. 74169/1983 (JP-A-58-74169) discloses a process which comprises, in a method of coating multi-focus lenses such as double-focus or triple-focus lenses with a hard coating agent or antifogging-coating agent, coating a plastic lens base having a boundary by means of dipping with holding the boundary of the lens at a right angle with respect to the liquid level or at an angle not greater than 20.degree. with respect to the perpendicular (right angle). This process is proposed for the purpose of inhibiting accumulation of the coating composition in the boundary part of the lens.
Japanese Patent Application Laid-open No. 294339/1990 (JP-A-2-294339) proposes an antifogging process which comprises immersing a plastic molded article such as a lens or an end plate (mirror board) with a polymerizable coating composition containing a water-soluble monomer, a monomer copolymerizable with this water-soluble monomer, and a polymerization initiator and harding the resultant immersed article for antifogging treatment.
However, even subjected to these antifogging treatments, the scratch resistance of articles can hardly be improved. That is, since the antifogging property due to the antifogging agent and the scratch resistance are in such an antinomy or contradictive relation that the scratch resistance is deteriorated with an increasing antifogging property, and the antifogging property is adversely affected with an enhancing scratch resistance, excellent antifogging property and high abrasion resistance are incompatible with each other. Therefore, when the antifogging property is improved, the spectacles or goggles tend to be scratched or abraded in case that the spectacles or goggles collide with dust or are in contact with or rubbed with other article when handled.
On the other hand, for the purpose of achieving high antifogging property and enhanced scratch resistance, there has been intended a process which comprises treating the inside surface of a lens with an antifogging agent and treating the outside surface of the lens with a hard coating agent. According to the dipping technology, however, the both sides of the lens are coated so that it is difficult to impart the antifogging property to the inside surface of the lens and the scratch resistance to the outside thereof, respectively. Further, there has been thought of coating one side and thereafter the other side of a lens base respectively with the use of spray coating or flow coating technology. According to this process, however, an equipment at high cost is required and the produc-tivity or yield tends to be deteriorated.
Incidentally, a lens having different functions on each side respectively may also be obtained by, for example, a process which comprises masking the inside surface of a plastic lens base with a masking agent, hard coating the outside surface by immersing, removing the masking by means of peeling, masking the hard coated surface and coating the inside surface with an antifogging agent by immersing, and removing the masking by stripping. This technology, however, requires a great number of steps and is complicated, and the productivity of lenses can hardly be improved. Further, when an organic solvent-based masking agent is directly coated to a plastic, removal of the masking agent is difficult because of great adhesion strength of the masking agent with respect to the plastic lens base. On the other hand, when a water-base latex paint is used as the masking agent, although the resultant masking coated layer can be peeled off or stripped from the plastic base, but it peels off or partially peels off, or is solved out in a succeeding step such as immersing step with the use of an organic solvent-based hard coating agent or antifogging agent, or washing or cleaning step. Accordingly, a masking agent having such an adequate adhesive strength as to have a high adhesive property with respect to a plastic base in the immersing step, and to be capable of peeling off after the immersing step would hardly be found out.
Furthermore, it is possible to use a masking film in lieu of a masking agent, but the film cannot be along concave and convex shape of the lens and, even when it is applied to a plane, the workability is deteriorated. Further, the surface which has not been treated with a hard coating agent has a tendency to be injured or scratched in laminating step, and the external appearance is sacrificed since an adhesion mark is remained after peeling off the film.